Suzu Hirose, second from left, plays an orphaned young Japanese woman who is welcomed into a newly discovered family in “Our Little Sister,” which has a refreshing take on female characters. (Sony Pictures Classics)

Hirokazu Kore-eda’s “Our Little Sister” glides gently through the ups and downs of its characters’ lives, like a boat riding slightly rippled waters. As in several of his previous works (“Still Walking,” “Like Father, Like Son”), the Japanese director takes on weighty familial themes, including separation and abandonment. But the emotional tone of this beautifully filmed drama is more restrained, at times to a fault.

Based on Akimi Yoshida’s serialized graphic novel “Umimachi Diary” (literally, “Seaside-Town Diary”), the live-action film centers on three 20-something sisters who have been on largely their own for many years. They’ve had no connection with either parent since their mother left them with their grandmother some 15 years earlier, after their father took up with another woman. Upon their father’s death, the trio travels to the countryside for his funeral, where they meet, for the first time, their half sister Suzu (Suzu Hirose), a shy girl in her early teens.

Not wanting to leave the now-orphaned Suzu with her neglectful stepmother — their father’s third wife — the three women invite her, on the spot, to come live with them. She soon joins them in their coastal home town of Kamakura, in the old house that once belonged to their late grandmother (which they jokingly refer to as a “girls’ dorm”).

What follows is a tender rendering of the bond that develops between Suzu and her siblings: conscientious nurse Sachi (Haruka Ayase); party-girl Yoshino (Masami Nagasawa), who works at a bank; and the hippie-ish Chika (Indou Kaho). As the three older siblings embrace her — in ways both sisterly and verging on the maternal — Suzu thrives in her new surroundings, excelling in sports and growing into a poised young woman. Scenes of daily life roll by, with a lovely backdrop of the changing seasons — cherry blossoms, summer fireworks — and a meditative piano score. The foursome delight in such simple pleasures as homemade plum wine and seafood dishes that bring back memories of absent family members.

The emphasis on female characters and their relationships is refreshing. The interactions among the sisters are the focus of the film. While they have occasional romances, their suitors, for the most part, stay in the background. Older women, including the girls’ great-aunt and the friendly owner of a local diner, figure more prominently.

To his credit, Kore-eda avoids oversentimentality in a narrative that could easily have indulged in it. Yet the unhurried pacing and minimal dramatic tension — even when an important character makes an appearance midway through the story — feels unsatisfying.

Indeed, it’s surprising how little conflict seemingly arises from the young women’s unexpected living arrangement, as they create a new family structure to replace the one their parents have failed to provide. But while the emotions may be muted, there’s still something appealingly heartfelt about the way these siblings find each other. One can’t help but cheer them on.

PG. At Landmark’s E Street Cinema. Contains mature themes, including parental loss, and brief strong language. In Japanese with subtitles. 126 minutes.